Cryogenic “Catering Truck” Comes to ALMA

The ultimate in high altitude, high-tech catering has arrived in Chile to serve chilled “provisions” to the antennas at the largest astronomical complex in the world, the Atacama Large Millimeter/submillimeter Array (ALMA).

Although it may look just like an airline catering truck, this vehicle is designed to carry something considerably more delicate than airplane meals! Each of the giant ALMA antennas contains a set of state-of-the-art, extremely sensitive superconducting receivers, or detectors, which are cryogenically cooled to –269 degrees Celsius (4 degrees above absolute zero). Until now, servicing these detectors has required moving the entire antenna, which weighs about 100 tonnes, from its observing site on the 5000-metre Chajnantor plateau down to the support facility at 2900 metres.

The newly arrived servicing truck, called the Front End Service Vehicle (FESV), is a custom designed truck packed with the equipment required to transport these delicate detector systems without having to move the entire antenna from the plateau. The truck moves its cargo cabin 6 metres vertically upwards, using a scissor lift, to align with the receiver cabin of an antenna, similar to catering trucks that align with aircraft doors, allowing personnel inside to replenish provisions directly at the airport gate.

Two FESVs were commissioned by the National Radio Astronomy Observatory (NRAO), part of the global ALMA partnership, with the help of one of their partners in ALMA, the Academia Sinica Institute of Astronomy and Astrophysics.

Each FESV has an air-conditioned cabin, and an on-board generator to keep the receivers cooled, which was provided by ESO. To move the cabinet containing the detectors into and out of the antenna’s receiver cabin, the FESV contains within it a custom-built forklift, called the Front End Handling Vehicle (FEHV).

When construction is completed in 2013, ALMA will have a total of 66 state-of-the-art antennas, which will work together as a single powerful telescope observing millimetre- and submillimetre-wavelength light. ALMA’s first scientific observations are planned to begin later this year with a partial array of antennas.

ALMA, an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

Courtesy of European Southern Observatory

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